1. Field of the Invention
The present invention pertains to an ultrasonic fragrance generation apparatus for buildings, vehicles, aircraft, and the like, as well as for open areas. In particular it pertains to an ultrasonic fragrance generation apparatus by which means a suitable fragrance may be dispersed into the ambient air at a suitable time in the optimum concentration.
2. Prior Art
Recently, there has been an increasing interest in improving the ambience in the atmosphere of living, working, traveling areas and the like through the use of fragrances. Such applications include not only masking tobacco stench and the like, but also actually exerting a physiological and psychological effect on the individuals present in the ambience.
Previously, this concept of fragrances exerting a physiological and psychological effect on human beings was known empirically as "aroma therapy". More recently, from research in the area of concomitant negative variation (CNV) of human brain waves, it has been verified that certain aromatic substances have calming, or conversely, stimulating physiological effects. For example, it has been shown that when lemon, or similar fragrances are dispersed in the air conditioning air of conference rooms, key-punch areas, and the like, that an increase in efficiency occurs and that loss of efficiency through fatigue is diminished. Similarly, rosemary and related substances have been shown to have a calming effect.
The stimulating effects of aromas related to lemon (group A), and conversely, the calming effects of rosemary and similar aromatic substances (group B), are shown below in Table 1.
TABLE 1 ______________________________________ Lemon Group Fragrances (A) Rosemary Group Fragrances (B) ______________________________________ Stimulation Sedation Increased efficiency Relaxation Increased alertness Restful sensation Less fatigue Diminished nervous tension Improved concentration ______________________________________
By using appropriate fragrances and by dispersing them according to a suitable time schedule, the desired effects may be optimized. Taking the example of an office, a group A fragrance and a group B fragrance may be dispersed according to the patterns shown in FIGS. 2 and 3 respectively, whereby a fragrance or mixture of fragrances having stimulating properties are dispersed during working hours and the sedating fragrances are dispersed during break periods. In the figures, N.sub.O indicates the lowest concentration of the fragrance detectable by the human nose (threshold value) and N.sub.1 indicates the concentration at which the fragrance is present during periods when its effect is not desired. It can be seen from the figures that even when the effect of the fragrance is unwanted, it is supplied at a low level below the threshold value. During the time blocks when it is desired to disperse the respective fragrance, its concentration is raised to a point above the threshold of detection by the human olfactory apparatus. Thereby, the appropriate fragrances are cycled throughout the day, each during its scheduled time zone, thus making it possible to accentuate the various "life rhythms" and at the same time, to constantly preserve the ideal ambience for the working environment. Furthermore, the advantageous properties of the various fragrances can best be used to enhance both the physical and mental well-being of those present in the controlled atmosphere.
In this way, using lemon group fragrances with mentally invigorating, stimulating (anti-drowzyness) properties, and thereby circulating an invigorating effect, lavender group fragrances with mentally calming, anti-stress, anti-anxiety, and anti-depressant properties, rosemary group fragrances with relaxing, appetite promoting properties, phytoncides with anti-microbial effects against virus and bacteria harmful to human physical well being, thus using these various fragrances and thereby enhancing the various life cycles has been proposed.
While fragrances are generally in a liquid form, the various individual components which make up a given fragrance ordinarily number in the tens to hundreds of which the volatilization properties may all be different. Therefore, when the various components making up a fragrance are allowed to volatilize naturally, those that volatilize most easily end up entering the vapor phase first. Accordingly, over time, the composition of both the fragrance given off and that of the fragrance liquid varies, and it is thus difficult to obtain the desired effect of the fragrance.
For these reasons, when supplying a fragrance to the atmospheres of buildings, vehicles, aircraft, and the like, as well as for open areas, rather that allowing the fragrant substances to volatilize spontaneously, it has recently been considered desirable to employ an ultrasonic fragrance generation apparatus or the like by which means a suitable fragrance may be dispersed into the ambient air at a suitable time in the optimum concentration, thereby dispersing the various components of the respective fragrances uniformly over time.
However, with existing ultrasonic devices for dispersing fragrances, the fragrance solution is dropped onto a vibrating surface whereby a thin liquid membrane is formed, this membrane then absorbing energy from the ultrasonic waves and thereby promptly vaporizing. With such a device, in order to disperse the fragrance efficiently, the liquid membrane formed on the vibrating surface must be formed very thin. Therefore, to increase the output, the surface area of the vibrating surface must be increased. But as the size of the vibrating surface area is increased, so must the size of the fragrance solution vaporization vessel and that of the apparatus as a whole. There are limits to the maximum suitable size for the apparatus, and thus accordingly, limits to the fragrance output for such a device.